Method of manufacturing electrolytic or electric-light carbons.



NITED STATES ATENT OFFICE.

HERBERT H. DOW, OF MIDLAND, MICHIGAN.

METHOD OF MANUFACTURING ELECTROLYTIC 0R ELECTRIC-LIGHT CARBONS.

SPECIFICATION forming part of Letters Patent No. 718,438, dated January 13, 1903.

Application filed November 6, 1899. Renewed April 13, 1901. vSerial No. 55,790. (No specimens.)

To all whom it may concern:

Be it known that I, HERBERT H. Dow, a citizen of the United States, and a resident of Midland, county of Midland, and State of Michigan, haveinvented a new and usefulImprovementin Methods of Manufacturing Electrolytic or Electric-Light Oarbons, of-which the following is a specification, the principle of the invention being herein explained and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

My invention relates to the production of a more perfect and uniform carbon for use in electrolytic processes or for use in electricarc lamps and also to cheapen the cost of such production.

The following description sets forth in detail one mode of carrying out the invention, such disclosed mode constituting but one of various ways in which the principle of the invention may be used.

The coke or other carbonaceous material is first ground to a powder of the requisite character and thenmixed by agitation, grinding while wet, or other suitable method with an emulsion consisting of a binder-such as tar, pitch, or the 1ikeand a liquid, such as water, in which such binder is insoluble or not readily soluble, whereby the binder is caused to exist throughout the mixture in a comminuted form and be homogeneously disseminated among the particles of carbon. The emulsion is first prepared by placing the binder and liquid in a suitable vessel and then violently agitating the two to form as nearly as possible a perfectly homogeneous molecular mixture, which is then added to and mixed with the powder, as above described. Another mode of making such emulsion and efiecting its mixturewith the carbonaceous powder is to place the powder, binder, and the liquid in a suitable agitating vessel, violently agitating the vessel for the time requisite to effect a suitable mixture of the binder and liquid, and the mixture of the emulsion so formed with the powder. The resulting mixture may then be freed of the liquid used for forming the emulsion by filtration, compression, or distillation, thereby permitting the coniminuted and thoroughlymixed binder to remain, contact, and bind the resulting mass is ready for molding and baking.

For electrolytic purposes carbons should be as dense as it is practical to make them and also as free as possible from hydrocarbons of every kind. Ordinary arc-light carbons contain more hydrocarbons and are also more porous than they should be for electrolytic use. This is due mainly to the fact that every particle of pulverized carbon cannot receive enough pitch to cement it without providing a great excess of pitch for some of the other particles when simply mechanical mixing is depended upon. By my method each particle will receive an amount of pitch in proportion to its size, thus making it possible to use a minimum amount of pitch, and consequently a minimum amount of porosity exists. A great deal of difficulty is experienced by manufacturers of arc-light carbons by the old method in being able to get a uniform conductivity for the reason that the pitch is in excess in certain parts and acts as an insulator. By my method more uniform re- .amount of baking can be obtained. A carbon is thus obtained of almost perfect uniformity in its molecular construction and at a great reduction in cost as compared with hitherto employed.

Other .modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the steps herein disclosed, provided the step or steps covered by any one of the following claims be employed.

I therefore particularly point out and distinctly claim as my invention 1. The step in a method of manufacturing carbons, which consists in mixing carbonaceous material with an emulsion of a binder and a liquid, substantially as set forth.

2. The step in a method of manufacturing carbons, which consists in mixing carbonaceous material with an emulsion of a binder and a liquid in which said binder is not readily soluble, substantially as set forth.

3. The step in a method of manufacture of carbons produced by the method and means the particles of carbon to each other, when suits and better conductivity with the same carbons, which consists in placing together powdered carbonaceous material, a suitable binder and a liquid in which said binder is insoluble or not readily soluble, and simultaneously forming an emulsion of said binder and liquid and a mixture of said emulsion and carbonaceous material, substantially as set forth.

4. The step in a method of manufacturing carbons, which consists in placing together powdered carbonaceous material, a suitable binder and a liquid in which said binder is not readily soluble and agitating or grinding such mixture whereby an emulsion of the binder and liquid and a mixture of such emul- 

